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<title>The C Preprocessor: Traditional Mode</title>

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Next: <a href="Implementation-Details.html#Implementation-Details" accesskey="n" rel="next">Implementation Details</a>, Previous: <a href="Preprocessor-Output.html#Preprocessor-Output" accesskey="p" rel="prev">Preprocessor Output</a>, Up: <a href="index.html#Top" accesskey="u" rel="up">Top</a> &nbsp; [<a href="index.html#SEC_Contents" title="Table of contents" rel="contents">Contents</a>][<a href="Index-of-Directives.html#Index-of-Directives" title="Index" rel="index">Index</a>]</p>
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<h2 class="chapter">10 Traditional Mode</h2>

<p>Traditional (pre-standard) C preprocessing is rather different from
the preprocessing specified by the standard.  When the preprocessor 
is invoked with the 
<samp>-traditional-cpp</samp> option, it attempts to emulate a traditional
preprocessor.  
</p>
<p>This mode is not useful for compiling C code with GCC, 
but is intended for use with non-C preprocessing applications.  Thus
traditional mode semantics are supported only when invoking
the preprocessor explicitly, and not in the compiler front ends.
</p>
<p>The implementation does not correspond precisely to the behavior of
early pre-standard versions of GCC, nor to any true traditional preprocessor.
After all, inconsistencies among traditional implementations were a
major motivation for C standardization.  However, we intend that it
should be compatible with true traditional preprocessors in all ways
that actually matter.
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<tr><td align="left" valign="top">&bull; <a href="Traditional-lexical-analysis.html#Traditional-lexical-analysis" accesskey="1">Traditional lexical analysis</a>:</td><td>&nbsp;&nbsp;</td><td align="left" valign="top">
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<tr><td align="left" valign="top">&bull; <a href="Traditional-macros.html#Traditional-macros" accesskey="2">Traditional macros</a>:</td><td>&nbsp;&nbsp;</td><td align="left" valign="top">
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<tr><td align="left" valign="top">&bull; <a href="Traditional-miscellany.html#Traditional-miscellany" accesskey="3">Traditional miscellany</a>:</td><td>&nbsp;&nbsp;</td><td align="left" valign="top">
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<tr><td align="left" valign="top">&bull; <a href="Traditional-warnings.html#Traditional-warnings" accesskey="4">Traditional warnings</a>:</td><td>&nbsp;&nbsp;</td><td align="left" valign="top">
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